Darkness comes early to the streets of this ancient city, once a symbol of Syria's richly storied past and now at the heart of the deepening nightmare that the country's revolution has become.

By 5 pm, people are scurrying home, down streets potholed by artillery, past piles of rubble and mountains of garbage that hasn't been collected in months, to spend the evenings huddled in the cold without heat, light or, increasingly, food.

"We just lie under blankets because it is so cold. We have no work, no money and no life," said Omar Abu Mohammed, 55, one of the few remaining residents of his badly bombed neighborhood, as he prepared to head indoors for the night.

"It is time to go now because soon there will be snipers," he added, as a shell boomed softly in the distance.

Shells are exploding somewhere in Aleppo most of the time, but after five months of fighting, people have become inured to the ever-present threat. Rain and cloudy skies have deterred warplanes, providing some relief from the airstrikes that can wipe out whole apartment buildings, along with their inhabitants, in an instant.

But the onset of this second winter since Syrians rose up against their government 21 months ago is bringing new calamity to a people already ground down by violence and war. Hunger, cold and disease are emerging as equally profound challenges in the desperate daily struggle that life has become for millions, not only in Aleppo but across Syria, where the quest for greater freedoms sparked by the Arab Spring has gone badly, horribly wrong.

"You can hide from the shelling, but if your child is hungry and there is no bread, what can you do?" asked Abdullah Awuf, 29, a driver who struggles to feed his infant son amid sky-high prices for fuel and food.

Aleppo is not the only place in Syria where conditions are dire. Across the country, reports are emerging of people foraging for food in garbage, stripping buildings for firewood and queuing for hours for scarce bread as the government-run distribution network breaks down.

The United Nations appealed last week for $1.5 billion to help 4.5 million needy Syrians, a record amount for an emergency, said Panos Moumtzis, the regional relief coordinator for the U.N. refugee agency. This one is unfolding almost entirely out of sight because most places are too dangerous or inaccessible for aid workers or journalists to visit.

Most of the relief money, $1 billion, will be spent to help the 500,000 refugees who have fled to neighboring countries. An additional 4 million people inside Syria are estimated to be in need of food and medical assistance.

But because the government restricts U.N. access to areas controlled by the regime, those living in rebel-held territory can expect to see little help.

In the parts of Aleppo under rebel control, the misery is manifest. Fighters with the opposition Free Syrian Army surged into the city in July hoping for a quick victory after ejecting government forces from much of the surrounding countryside. But their offensive was ill-planned and premature, and it quickly stalled, leaving the city carved into a patchwork of front lines across which the two sides shoot and shell each other, along with any civilians in the way.

Government forces control the downtown area and the wealthier neighborhoods to the west, while the rebels hold sway in the traditionally poorer northern, eastern and southern areas. The historic center, a World Heritage site renowned for its ancient citadel and bazaar, is a battleground.

As the fighting ripples and spreads, the infrastructure that had sustained the city of 3 million is crumbling. Government warplanes target facilities that fall into rebel hands, including hospitals and bakeries. Electricity, which had been intermittent for months, has been cut off since the rebels launched an offensive to capture the main power plant a little more than two weeks ago.

An Aleppo Transitional Revolutionary Council is being formed to perform the functions of local government. It has managed to ease, though not resolve, an acute shortage of bread that had people standing in line for up to 16 hours. There are still queues, but they have shortened, and people say they now have to wait no more than an hour to buy bread.

But the length of the lines is only a partial measure of the crisis. Factories and businesses have ground to a halt. Jobs are almost nonexistent. Fresh meat and produce are available, but at prices far beyond the means of people who haven't worked in months. For many, flat, thin loaves of pita bread, at 10 times the prewar price, are all they can afford. For some, even that is too much.

"On some days, we don't eat at all," said Nadia Labhan, 25, whose husband, a brickmaker, was killed two months ago by a sniper on his way home from buying bread, leaving her with no means to support her two children, Baraa, 7, and Fatme, 5. She has joined the growing number of beggars on the street. "It is so difficult," she said, hugging her flimsy robe against the driving wind and rain.

Inevitably, disease is spreading among people whose immune systems have been weakened by hunger, in a city where sanitation has broken down. Tuberculosis is ravaging some neighborhoods, and there have been hundreds of cases of leishmaniasis, a skin disease transmitted by sand flies, which are multiplying amid the heaps of uncollected trash, said Saad Wafai, who serves on the crisis committee of the Aleppo council.

At a small clinic in an abandoned shopping arcade — set up by doctors driven out of a hospital destroyed in an airstrike — the number of patients has surged recently, to about 150 a day. For the first time, physician Izzat al-Mizyad said, most show up not with injuries from the war but infectious diseases, including hepatitis, respiratory infections and scabies.

In addition, he said, two or three people are brought in every day after collapsing from hunger in the bread lines. "This is going to become a huge problem," he said. "It is already a problem, and it is increasing day by day. I expect people to start to die."

Embittered Aleppans don't see an end in sight.

"It started with words, then went to bullets, then bombs and rockets and airstrikes. And now we are expecting chemical weapons," said Awuf, the driver, referring to the trajectory of the revolt, which began with peaceful demonstrations in March 2011, then mutated into a raging civil war.

Some blame the Free Syrian Army for starting a fight it couldn't finish. Others blame the government for steadily escalating the use of force to try to crush the rebels. Many, like Awuf, blame both. "We are civilians trapped between the two sides, and they are using us like wood on a fire," he said. "Both sides are wrong."

Even the uprising's staunchest protagonists are beginning to despair. Teacher Amal Ulabi, 35, joined the earliest protests, and her husband volunteered for the Free Syrian Army as soon as the rebellion reached the city. A month later, he was dead, killed fighting on the front line. Her home in the embattled Old City was hit by artillery fire, and she has moved to her parents' house with her five children. They suffer from asthma, and all have respiratory infections, but there is no medicine available to treat them.

"The revolution was the right thing to do, but the timing was wrong," Ulabi said at a clinic established by a group called People in Need, sighing as she waited for a nurse to check on her 18-month-old son. "We should have started gradually, asking about corruption and other issues like that, because the regime couldn't accept that we suddenly wanted freedom, and they shot at us.

"The regime will fall, but I fear it will take time," she added. "At least as long as we have endured already. I see no hope of anything good."

Tourists are limp, leaderless and distinctly UnAustralian

Andrew Grice: Inside Westminster

Blairites be warned, this could be the moment Labour turns into Syriza

The mystery of Britain's worst naval disaster is finally solved - 271 years later

Exclusive: David Keys reveals the research that finally explains why HMS Victory went down with the loss of 1,100 lives

'I saw people so injured you couldn't tell if they were dead or alive'

Nagasaki survivors on why Japan must not abandon its post-war pacifism

The voter Obama tried hardest to keep onside

Outgoing The Daily Show host, Jon Stewart, became the voice of Democrats who felt the President had failed to deliver on his ‘Yes We Can’ slogan. Tim Walker charts the ups and downs of their 10-year relationship on screen